The end axles (10a, 10b) have live-axle journal receiving holes thereon.

The rotor has magnet housing holes formed therein while a plurality of magnetic poles constituted by permanent magnets inserted into the magnet housing holes being circumferentially arranged in the rotor.

The discharging ends (531, 532) are disposed in the corresponding accommodating holes (511, 512).

The introduction hole and/or housing holes lead to separate surfaces from the front side.

At least two groups of seat holes (14) are set up along the longitudinal direction of the launch tube (1), and each group has at least two seat holes (14) which are radial symmetry arranged with each other.

The housing (51) is provided with at least two accommodating holes (511, 512) corresponding to the discharging ends (531, 532).

The housing (41) is provided with at least two accommodating holes (411, 412) corresponding to the discharging ends (431, 432).

An elongated precision measuring channel (3a, 3b, 3c) is allocated and arranged parallel to said slots (8).

Several locating slots (8a, 8b, 8c) for tools having the same diameter are allocated to at least the precision measuring channels (3a, 3b, 3c).

Several precision measuring channels (3a, 3b, 3c) are arranged in a substantially parallel manner in the support device.

The discharging ends (431, 432) are disposed in the corresponding accommodating holes (411, 412), and protrude from an external surface of the housing (41).

When assembling, the live-axle journals (4a, 4b) are respectively inserted into the corresponding live-axle journal receiving holes and rotatablely connected with the end axles (10a, 10b).

The housing also has a plurality of holes of the cavity bottom, the housing holes to be in alignment with the bush holes.

The housing is provided with a plurality of through holes passing through the wall.

The insert may be keyed into the housing to ensure the extrusion holes of the insert align with extension holes in the housing.